After profilation check the contents of the %temp%\JetLogs. If there are some files containing 'Core' in their names, then it means that profilation started and core was loaded but died of exception. If there were no 'Core' files, then it mean the profilation didn't start.

If there are no log with 'Core' in the file name, then check if there were some lgc*.* files in the %temp% folder.

The original post fixed my problem when running locally, but I still get the same error as the screenshot when trying to run the profiler remote.

I can telnet the agent and the local profiler configuration can connect to the remote server agent (using default port 9000 and a passphrase). The remote agent reports "Authenticated as passphrase match" once setting up the profiler and then again once when running the profiler (without "start immediately"). After that I get the same dialog as shown in the screendump in the original message. The list of w3wp.exe processes is empty. The agent writes nothing anymore in the console.

Do I have to set any folder permissions on the remote server? I tried adding IIS_IUSRS to the agent exe folder, but that didn't help.

dotTrace Performance v4.x uses .NET remoting technology for profiling remote application. In fact this technology is bad for our purposes. It requires bidirectional connection for computers through TCP. It means both computers have to be in the same network and have their firewalls disabled. Please check that your configuration is compatible with the requirements.

What helped me is to restore my system using a restore point set to several days ago, and reinstall JetBrains dotTrace completely.

Sounds crazy, but nothing helped, including all advices above. I have also tried to clean up registry entries, Windows Services, temporary folders, uninstall dotTrace and install it again. Profiler haven't started until system restore + reinstalling.

Possible problem 1: after I first installed JetBrains dotTrace, I have also installed RedGate Ants profiler. But uninstalling it with registry cleanup also wasn't helpful, and I should say that some colleagues of mine use both profilers at a time successfully.

Possible problem 2: in my Application Event Log I started to receive errors from .Net Runtime with text "Failed to CoCreate profiler." I blamed this exception for profiler not working before. However, now my profiler works fine despite these messages.

Possible problem 3: When profiler didn't start, in JetLogs, ExternalLauncherProcess log the last message of each profiling session was: